<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
	</body>
	<script>
		    (function (name, factory) {
		        if (typeof window === "object") {
		            window[name] = factory();
		        }
		    })("Ribbons", function () {
		        var _w = window, _b = document.body, _d = document.documentElement;
		        var random = function () {
		            if (arguments.length === 1) {
		                if (Array.isArray(arguments[0])) {
		                    var index = Math.round(random(0, arguments[0].length - 1));
		                    return arguments[0][index];
		                }
		                return random(0, arguments[0]);
		            } else if (arguments.length === 2) {
		                return Math.random() * (arguments[1] - arguments[0]) + arguments[0];
		            }
		            return 0;
		        };
		        var screenInfo = function (e) {
		            var width = Math.max(0, _w.innerWidth || _d.clientWidth || _b.clientWidth || 0),
		                height = Math.max(0, _w.innerHeight || _d.clientHeight || _b.clientHeight || 0),
		                scrollx = Math.max(0, _w.pageXOffset || _d.scrollLeft || _b.scrollLeft || 0) - (_d.clientLeft || 0),
		                scrolly = Math.max(0, _w.pageYOffset || _d.scrollTop || _b.scrollTop || 0) - (_d.clientTop || 0);
		            return {
		                width: width,
		                height: height,
		                ratio: width / height,
		                centerx: width / 2,
		                centery: height / 2,
		                scrollx: scrollx,
		                scrolly: scrolly
		            };
		        };
		        var mouseInfo = function (e) {
		            var screen = screenInfo(e), mousex = e ? Math.max(0, e.pageX || e.clientX || 0) : 0,
		                mousey = e ? Math.max(0, e.pageY || e.clientY || 0) : 0;
		            return {
		                mousex: mousex,
		                mousey: mousey,
		                centerx: mousex - screen.width / 2,
		                centery: mousey - screen.height / 2
		            };
		        };
		        var Point = function (x, y) {
		            this.x = 0;
		            this.y = 0;
		            this.set(x, y);
		        };
		        Point.prototype = {
		            constructor: Point, set: function (x, y) {
		                this.x = x || 0;
		                this.y = y || 0;
		            }, copy: function (point) {
		                this.x = point.x || 0;
		                this.y = point.y || 0;
		                return this;
		            }, multiply: function (x, y) {
		                this.x *= x || 1;
		                this.y *= y || 1;
		                return this;
		            }, divide: function (x, y) {
		                this.x /= x || 1;
		                this.y /= y || 1;
		                return this;
		            }, add: function (x, y) {
		                this.x += x || 0;
		                this.y += y || 0;
		                return this;
		            }, subtract: function (x, y) {
		                this.x -= x || 0;
		                this.y -= y || 0;
		                return this;
		            }, clampX: function (min, max) {
		                this.x = Math.max(min, Math.min(this.x, max));
		                return this;
		            }, clampY: function (min, max) {
		                this.y = Math.max(min, Math.min(this.y, max));
		                return this;
		            }, flipX: function () {
		                this.x *= -1;
		                return this;
		            }, flipY: function () {
		                this.y *= -1;
		                return this;
		            }
		        };
		        var Factory = function (options) {
		            this._canvas = null;
		            this._context = null;
		            this._sto = null;
		            this._width = 0;
		            this._height = 0;
		            this._scroll = 0;
		            this._ribbons = [];
		            this._options = {
		                //色彩饱和度
		                colorSaturation: "80%",
		                //色彩亮度
		                colorBrightness: "80%",
		                //色彩透明度
		                colorAlpha: 0.5,
		                //丝带不同块之间的色彩变化量
		                colorCycleSpeed: 5,
		                //丝带相对于屏幕的初始位置：top/min 屏幕最上方，middle|center 中间，bottom|max 屏幕最下面，random随机
		                verticalPosition: "random",
		                //丝带水平方向移动速度参数（会乘以一个随机值）
		                horizontalSpeed: 200,
		                //同一时间丝带总条数
		                ribbonCount: 4,
		                strokeSize: 0,
		                //滚动偏移参数，-1表示不偏移，0表示基于丝带只出现在页面最上面
		                parallaxAmount: -0.2,
		                animateSections: true
		            };
		            this._onDraw = this._onDraw.bind(this);
		            this._onResize = this._onResize.bind(this);
		            this._onScroll = this._onScroll.bind(this);
		            this.setOptions(options);
		            this.init();
		        };
		        Factory.prototype = {
		            constructor: Factory, setOptions: function (options) {
		                if (typeof options === "object") {
		                    for (var key in options) {
		                        if (options.hasOwnProperty(key)) {
		                            this._options[key] = options[key];
		                        }
		                    }
		                }
		            }, init: function () {
		                try {
		                    this._canvas = document.createElement("canvas");
		                    this._canvas.style["display"] = "block";
		                    this._canvas.style["position"] = "fixed";
		                    this._canvas.style["margin"] = "0";
		                    this._canvas.style["padding"] = "0";
		                    this._canvas.style["border"] = "0";
		                    this._canvas.style["outline"] = "0";
		                    this._canvas.style["left"] = "0";
		                    this._canvas.style["top"] = "0";
		                    this._canvas.style["width"] = "100%";
		                    this._canvas.style["height"] = "100%";
		                    this._canvas.style["z-index"] = "-1";
		                    this._canvas.style["background-color"] = "#fff";
		                    this._canvas.id = "bgCanvas";
		                    this._onResize();
		                    this._context = this._canvas.getContext("2d");
		                    this._context.clearRect(0, 0, this._width, this._height);
		                    this._context.globalAlpha = this._options.colorAlpha;
		                    // 这里可以设置是否随着窗口的滚动而滚动
		                    window.addEventListener("resize", this._onResize);
		                    window.addEventListener("scroll", this._onScroll);
		                    // 这里设置添加的位置
		                    var body_ = document.getElementsByTagName('body')[0];
		                    body_.appendChild(this._canvas);
		                } catch (e) {
		                    console.warn("Canvas Context Error: " + e.toString());
		                    return;
		                }
		                //开始绘画
		                this._onDraw();
		            }, addRibbon: function () {
		                var dir = Math.round(random(1, 9)) > 5 ? "right" : "left", stop = 1000, hide = 200, min = 0 - hide,//丝带延伸方向
		                    max = this._width + hide, movex = 0, movey = 0, startx = dir === "right" ? min : max,
		                    starty = Math.round(random(0, this._height));
		                //丝带生成的位置
		                if (/^(top|min)$/i.test(this._options.verticalPosition)) {//最上方
		                    starty = 0 + hide;
		                } else if (/^(middle|center)$/i.test(this._options.verticalPosition)) {//中间
		                    starty = this._height / 2;
		                } else if (/^(bottom|max)$/i.test(this._options.verticalPosition)) {//最下方
		                    starty = this._height - hide;
		                }
		                var ribbon = [], point1 = new Point(startx, starty), point2 = new Point(startx, starty), point3 = null,
		                    color = Math.round(random(0, 360)), delay = 0;
		                while (true) {
		                    if (stop <= 0) break;
		                    stop--;
		                    movex = Math.round((Math.random() * 1 - 0.2) * this._options.horizontalSpeed);
		                    movey = Math.round((Math.random() * 1 - 0.5) * (this._height * 0.25));
		                    point3 = new Point();
		                    point3.copy(point2);
		                    if (dir === "right") {
		                        point3.add(movex, movey);
		                        if (point2.x >= max) break;
		                    } else if (dir === "left") {
		                        point3.subtract(movex, movey);
		                        if (point2.x <= min) break;
		                    }
		                    ribbon.push({
		                        point1: new Point(point1.x, point1.y),
		                        point2: new Point(point2.x, point2.y),
		                        point3: point3,
		                        color: color,
		                        delay: delay,//延迟消失
		                        dir: dir,//方向
		                        alpha: 0,//透明度
		                        phase: 0//透明度
		                    });
		                    point1.copy(point2);
		                    point2.copy(point3);
		                    delay += 4;
		                    color += this._options.colorCycleSpeed;
		                }
		                this._ribbons.push(ribbon);
		            }, _drawRibbonSection: function (section) {
		                if (section) {
		                    if (section.phase >= 1 && section.alpha <= 0) {
		                        return true;
		                    }
		                    if (section.delay <= 0) {
		                        section.phase += 0.02;
		                        section.alpha = Math.sin(section.phase) * 1;
		                        section.alpha = section.alpha <= 0 ? 0 : section.alpha;
		                        section.alpha = section.alpha >= 1 ? 1 : section.alpha;
		                        if (this._options.animateSections) {
		                            var mod = Math.sin(1 + section.phase * Math.PI / 2) * 0.1;
		                            if (section.dir === "right") {
		                                section.point1.add(mod, 0);
		                                section.point2.add(mod, 0);
		                                section.point3.add(mod, 0);
		                            } else {
		                                section.point1.subtract(mod, 0);
		                                section.point2.subtract(mod, 0);
		                                section.point3.subtract(mod, 0);
		                            }
		                            section.point1.add(0, mod);
		                            section.point2.add(0, mod);
		                            section.point3.add(0, mod);
		                        }
		                    } else {
		                        section.delay -= 0.5;
		                    }
		                    var s = this._options.colorSaturation, l = this._options.colorBrightness,
		                        c = "hsla(" + section.color + ", " + s + ", " + l + ", " + section.alpha + " )";
		                    this._context.save();
		                    if (this._options.parallaxAmount !== 0) {
		                        this._context.translate(0, this._scroll * this._options.parallaxAmount);
		                    }
		                    this._context.beginPath();
		                    this._context.moveTo(section.point1.x, section.point1.y);
		                    this._context.lineTo(section.point2.x, section.point2.y);
		                    this._context.lineTo(section.point3.x, section.point3.y);
		                    this._context.fillStyle = c;
		                    this._context.fill();
		                    if (this._options.strokeSize > 0) {
		                        this._context.lineWidth = this._options.strokeSize;
		                        this._context.strokeStyle = c;
		                        this._context.lineCap = "round";
		                        this._context.stroke();
		                    }
		                    this._context.restore();
		                }
		                return false;
		            }, _onDraw: function () {
		                for (var i = 0, t = this._ribbons.length; i < t; ++i) {
		                    if (!this._ribbons[i]) {
		                        this._ribbons.splice(i, 1);
		                    }
		                }
		                this._context.clearRect(0, 0, this._width, this._height);
		                for (var a = 0; a < this._ribbons.length; ++a) {
		                    var ribbon = this._ribbons[a], numSections = ribbon.length, numDone = 0;
		                    for (var b = 0; b < numSections; ++b) {
		                        if (this._drawRibbonSection(ribbon[b])) {
		                            numDone++;
		                        }
		                    }
		                    if (numDone >= numSections) {
		                        this._ribbons[a] = null;
		                    }
		                }
		                if (this._ribbons.length < this._options.ribbonCount) {
		                    this.addRibbon();
		                }
		                requestAnimationFrame(this._onDraw);
		            }, _onResize: function (e) {
		                var screen = screenInfo(e);
		                this._width = screen.width;
		                this._height = screen.height;
		                if (this._canvas) {
		                    this._canvas.width = this._width;
		                    this._canvas.height = this._height;
		                    if (this._context) {
		                        this._context.globalAlpha = this._options.colorAlpha;
		                    }
		                }
		            }, _onScroll: function (e) {
		                var screen = screenInfo(e);
		                this._scroll = screen.scrolly;
		            }
		        };
		        return Factory;
		    });
		    new Ribbons();
	</script>
</html>
